Re: [PATCH V6 06/21] clk: tegra: pll: Save and restore pll context

Dmitry Osipenko
2019-07-21T21:44:40Z

21.07.2019 22:40, Sowjanya Komatineni пишет:
> This patch implements save and restore of PLL context.
>
> During system suspend, core power goes off and looses the settings
> of the Tegra CAR controller registers.
>
> So during suspend entry pll rate is stored and on resume it is
> restored back along with its state.
>
> Acked-by: Thierry Reding <treding@nvidia.com>
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
> drivers/clk/tegra/clk-pll.c | 121 ++++++++++++++++++++++++++++-----------
> drivers/clk/tegra/clk-tegra210.c | 2 +-
> drivers/clk/tegra/clk.h | 10 +++-
> 3 files changed, 99 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/clk/tegra/clk-pll.c b/drivers/clk/tegra/clk-pll.c
> index 1583f5fc992f..f136964e6c44 100644
> --- a/drivers/clk/tegra/clk-pll.c
> +++ b/drivers/clk/tegra/clk-pll.c
> @@ -1008,6 +1008,59 @@ static unsigned long clk_plle_recalc_rate(struct clk_hw *hw,
> return rate;
> }
>
> +void tegra_clk_sync_state_pll(struct clk_hw *hw)
> +{
> + if (!__clk_get_enable_count(hw->clk))
> + clk_pll_disable(hw);
> + else
> + clk_pll_enable(hw);
> +}
> +
> +static int tegra_clk_pll_save_context(struct clk_hw *hw)
> +{
> + struct tegra_clk_pll *pll = to_clk_pll(hw);
> + u32 val = 0;
> +
> + pll->rate = clk_hw_get_rate(hw);
> +
> + if (pll->params->flags & TEGRA_PLLMB)
> + val = pll_readl_base(pll);
> + else if (pll->params->flags & TEGRA_PLLRE)
> + val = pll_readl_base(pll) & divp_mask_shifted(pll);
> +
> + pll->pllbase_ctx = val;
> +
> + return 0;
> +}
> +
> +static void tegra_clk_pll_restore_context(struct clk_hw *hw)
> +{
> + struct tegra_clk_pll *pll = to_clk_pll(hw);
> + struct clk_hw *parent = clk_hw_get_parent(hw);
> + unsigned long parent_rate = clk_hw_get_rate(parent);
> + u32 val;
> +
> + if (clk_pll_is_enabled(hw))
> + return;
> +
> + if (pll->params->flags & TEGRA_PLLMB) {
> + pll_writel_base(pll->pllbase_ctx, pll);
> + } else if (pll->params->flags & TEGRA_PLLRE) {
> + val = pll_readl_base(pll);
> + val &= ~(divp_mask_shifted(pll));
> + pll_writel_base(pll->pllbase_ctx | val, pll);
> + }
> +
> + if (pll->params->set_defaults)
> + pll->params->set_defaults(pll);
> +
> + clk_pll_set_rate(hw, pll->rate, parent_rate);
> +
> + /* do not sync pllx state here. pllx is sync'd after dfll resume */
> + if (!(pll->params->flags & TEGRA_PLLX))
> + tegra_clk_sync_state_pll(hw);
> +}
> +
> const struct clk_ops tegra_clk_pll_ops = {
> .is_enabled = clk_pll_is_enabled,
> .enable = clk_pll_enable,
> @@ -1015,6 +1068,8 @@ const struct clk_ops tegra_clk_pll_ops = {
> .recalc_rate = clk_pll_recalc_rate,
> .round_rate = clk_pll_round_rate,
> .set_rate = clk_pll_set_rate,
> + .save_context = tegra_clk_pll_save_context,
> + .restore_context = tegra_clk_pll_restore_context,
> };
>
> const struct clk_ops tegra_clk_plle_ops = {
> @@ -1802,6 +1857,27 @@ static int clk_pllu_tegra114_enable(struct clk_hw *hw)
>
> return ret;
> }
> +
> +static void _clk_plle_tegra_init_parent(struct tegra_clk_pll *pll)
> +{
> + u32 val, val_aux;
> +
> + /* ensure parent is set to pll_ref */
> + val = pll_readl_base(pll);
> + val_aux = pll_readl(pll->params->aux_reg, pll);
> +
> + if (val & PLL_BASE_ENABLE) {
> + if ((val_aux & PLLE_AUX_PLLRE_SEL) ||
> + (val_aux & PLLE_AUX_PLLP_SEL))
> + WARN(1, "pll_e enabled with unsupported parent %s\n",
> + (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
> + "pll_re_vco");
> + } else {
> + val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
> + pll_writel(val_aux, pll->params->aux_reg, pll);
> + fence_udelay(1, pll->clk_base);
> + }
> +}
> #endif
>
> static struct tegra_clk_pll *_tegra_init_pll(void __iomem *clk_base,
> @@ -2214,27 +2290,12 @@ struct clk *tegra_clk_register_plle_tegra114(const char *name,
> {
> struct tegra_clk_pll *pll;
> struct clk *clk;
> - u32 val, val_aux;
>
> pll = _tegra_init_pll(clk_base, NULL, pll_params, lock);
> if (IS_ERR(pll))
> return ERR_CAST(pll);
>
> - /* ensure parent is set to pll_re_vco */
> -
> - val = pll_readl_base(pll);
> - val_aux = pll_readl(pll_params->aux_reg, pll);
> -
> - if (val & PLL_BASE_ENABLE) {
> - if ((val_aux & PLLE_AUX_PLLRE_SEL) ||
> - (val_aux & PLLE_AUX_PLLP_SEL))
> - WARN(1, "pll_e enabled with unsupported parent %s\n",
> - (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
> - "pll_re_vco");
> - } else {
> - val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
> - pll_writel(val_aux, pll_params->aux_reg, pll);
> - }
> + _clk_plle_tegra_init_parent(pll);
>
> clk = _tegra_clk_register_pll(pll, name, parent_name, flags,
> &tegra_clk_plle_tegra114_ops);
> @@ -2276,6 +2337,8 @@ static const struct clk_ops tegra_clk_pllss_ops = {
> .recalc_rate = clk_pll_recalc_rate,
> .round_rate = clk_pll_ramp_round_rate,
> .set_rate = clk_pllxc_set_rate,
> + .save_context = tegra_clk_pll_save_context,
> + .restore_context = tegra_clk_pll_restore_context,
> };
>
> struct clk *tegra_clk_register_pllss(const char *name, const char *parent_name,
> @@ -2375,6 +2438,7 @@ struct clk *tegra_clk_register_pllre_tegra210(const char *name,
> pll_params->vco_min = pll_params->adjust_vco(pll_params,
> parent_rate);
>
> + pll_params->flags |= TEGRA_PLLRE;
> pll = _tegra_init_pll(clk_base, pmc, pll_params, lock);
> if (IS_ERR(pll))
> return ERR_CAST(pll);
> @@ -2520,11 +2584,19 @@ static void clk_plle_tegra210_disable(struct clk_hw *hw)
> spin_unlock_irqrestore(pll->lock, flags);
> }
>
> +static void tegra_clk_plle_t210_restore_context(struct clk_hw *hw)
> +{
> + struct tegra_clk_pll *pll = to_clk_pll(hw);
> +
> + _clk_plle_tegra_init_parent(pll);
> +}
> +
> static const struct clk_ops tegra_clk_plle_tegra210_ops = {
> .is_enabled = clk_plle_tegra210_is_enabled,
> .enable = clk_plle_tegra210_enable,
> .disable = clk_plle_tegra210_disable,
> .recalc_rate = clk_pll_recalc_rate,
> + .restore_context = tegra_clk_plle_t210_restore_context,
> };
>
> struct clk *tegra_clk_register_plle_tegra210(const char *name,
> @@ -2535,27 +2607,12 @@ struct clk *tegra_clk_register_plle_tegra210(const char *name,
> {
> struct tegra_clk_pll *pll;
> struct clk *clk;
> - u32 val, val_aux;
>
> pll = _tegra_init_pll(clk_base, NULL, pll_params, lock);
> if (IS_ERR(pll))
> return ERR_CAST(pll);
>
> - /* ensure parent is set to pll_re_vco */
> -
> - val = pll_readl_base(pll);
> - val_aux = pll_readl(pll_params->aux_reg, pll);
> -
> - if (val & PLLE_BASE_ENABLE) {
> - if ((val_aux & PLLE_AUX_PLLRE_SEL) ||
> - (val_aux & PLLE_AUX_PLLP_SEL))
> - WARN(1, "pll_e enabled with unsupported parent %s\n",
> - (val_aux & PLLE_AUX_PLLP_SEL) ? "pllp_out0" :
> - "pll_re_vco");
> - } else {
> - val_aux &= ~(PLLE_AUX_PLLRE_SEL | PLLE_AUX_PLLP_SEL);
> - pll_writel(val_aux, pll_params->aux_reg, pll);
> - }
> + _clk_plle_tegra_init_parent(pll);
>
> clk = _tegra_clk_register_pll(pll, name, parent_name, flags,
> &tegra_clk_plle_tegra210_ops);
> diff --git a/drivers/clk/tegra/clk-tegra210.c b/drivers/clk/tegra/clk-tegra210.c
> index 4721ee030d1c..58397f93166c 100644
> --- a/drivers/clk/tegra/clk-tegra210.c
> +++ b/drivers/clk/tegra/clk-tegra210.c
> @@ -1602,7 +1602,7 @@ static struct tegra_clk_pll_params pll_x_params = {
> .pdiv_tohw = pll_qlin_pdiv_to_hw,
> .div_nmp = &pllx_nmp,
> .freq_table = pll_x_freq_table,
> - .flags = TEGRA_PLL_USE_LOCK | TEGRA_PLL_HAS_LOCK_ENABLE,
> + .flags = TEGRA_PLL_USE_LOCK | TEGRA_PLL_HAS_LOCK_ENABLE | TEGRA_PLLX,
> .dyn_ramp = tegra210_pllx_dyn_ramp,
> .set_defaults = tegra210_pllx_set_defaults,
> .calc_rate = tegra210_pll_fixed_mdiv_cfg,
> diff --git a/drivers/clk/tegra/clk.h b/drivers/clk/tegra/clk.h
> index fb29a8c27873..8532f5150091 100644
> --- a/drivers/clk/tegra/clk.h
> +++ b/drivers/clk/tegra/clk.h
> @@ -235,6 +235,8 @@ struct tegra_clk_pll;
> * TEGRA_PLLMB - PLLMB has should be treated similar to PLLM. This
> * flag indicated that it is PLLMB.
> * TEGRA_PLL_VCO_OUT - Used to indicate that the PLL has a VCO output
> + * TEGRA_PLLRE - Used to indicate that it is PLLRE.
> + * TEGRA_PLLX - Used to indicate that it is PLLX.
> */
> struct tegra_clk_pll_params {
> unsigned long input_min;
> @@ -301,6 +303,8 @@ struct tegra_clk_pll_params {
> #define TEGRA_MDIV_NEW BIT(11)
> #define TEGRA_PLLMB BIT(12)
> #define TEGRA_PLL_VCO_OUT BIT(13)
> +#define TEGRA_PLLRE BIT(14)
> +#define TEGRA_PLLX BIT(15)
>
> /**
> * struct tegra_clk_pll - Tegra PLL clock
> @@ -310,6 +314,8 @@ struct tegra_clk_pll_params {
> * @pmc: address of PMC, required to read override bits
> * @lock: register lock
> * @params: PLL parameters
> + * @rate: rate during system suspend and resume
> + * @pllbase_ctx: pll base register value during suspend and resume
> */
> struct tegra_clk_pll {
> struct clk_hw hw;
> @@ -317,6 +323,8 @@ struct tegra_clk_pll {
> void __iomem *pmc;
> spinlock_t *lock;
> struct tegra_clk_pll_params *params;
> + unsigned long rate;
> + u32 pllbase_ctx;
> };
>
> #define to_clk_pll(_hw) container_of(_hw, struct tegra_clk_pll, hw)
> @@ -840,7 +848,7 @@ u16 tegra_pll_get_fixed_mdiv(struct clk_hw *hw, unsigned long input_rate);
> int tegra_pll_p_div_to_hw(struct tegra_clk_pll *pll, u8 p_div);
> int div_frac_get(unsigned long rate, unsigned parent_rate, u8 width,
> u8 frac_width, u8 flags);
> -
> +void tegra_clk_sync_state_pll(struct clk_hw *hw);

Looks like this function isn't used anywhere other than this patch. Bug?

> /* Combined read fence with delay */
> #define fence_udelay(delay, reg) \
>